In order to put a large 2500 litre tank in greenhouse, the pavement was done.
We were extremely lucky. In order to clean up construction site I was working at, I got enough basalt groats and fine sand to make bed for pavement plates (also used). Dirt was removed, the felt placed under groats and then compressed. Used concrete plates were layed on fine groat. Al gaps were filled with fine sand.
It was time to get large water tank. We had it in our house for heating oil storage. We didn’t need it any more, because we heat our house on solar energy and wood from our own forest. It was so tightly placed between the walls, there was only centimetre on each side, but we managed to get it out 🙂
Eva painted it black, so it will absorb more energy (heat) from sun. Eva did all the painting in greenhouse to!
The main idea of the tank is: Large black tank is full of water. In sunny days the temperature of water will rise and in cold days and nights it will radiate that energy inside greenhouse. Example: 2500 litres of water have 20°C during day. Next morning water have only 18°C. All the energy that was taken from water in tank is in greenhouse air now. That would be 21 MJ!
Well I have to make some measuring of actual temperature differences between evening and morning to get the right numbers.
I was so into work, that I forgot to take pictures step by step. Our next step was to make the connection between ground/foundations and walls. So we bought prestressed concrete planks (3.0 and 2.5 m long, 5.0 cm thick) and I cut them, so it fit between foundations. All the gaps were later sealed with elastic frost resistant cement glue.
Now it was possible to close the walls. South, west and east walls are closed up with same polycarbonate plates as roof. North wall is made of 20mm wood board + 100 mm glasswoll insulation + 20mm wood board. Well, I found local manufacturer of profiled wood boards. It’s much cheaper this way and money stays in local district.
After first wall was built, I did electricity box with consumption meter and LED lights (3x 10W reflectors), keeping in mind we might install solar panels later.
As I wrote in “Why”, I have my rough design idea. That idea must be developed into cost-effective design to reduce material waste, solve details and predict weak points in workflow.
I researched little about polycarbonate panels, that will be used for roof. Polycarbonate comes in different sizes and thickness. I choose 16 mm thick plates, because of insulation and load capacity (we can have a lot of snow). Width is 2100 mm and length is available in 4000, 6000 or 7000 mm. To minimize polycarbonate waste, both sides of the roof must have total length of plate. I adjusted width of greenhouse to fit 6000 mm plates (see first screenshot, A+B=6000 mm)
Second, wood frame must be adjusted to fit 2100 mm plates. Greenhouse will have 10 cm cordon (overhang) around it. In assembly plan for polycarbonate (PC) plates is detail of 20 mm gap between plates, to fit sealing profile. So it also follows, distances between foundations will be 1.96 m, 2.12 m, 2.12 m and 1.96 m (see second screenshot).
Foundations will be simple. Drilled hole in ground will be filled with concrete and insterted profile for wood frame.